A silicon carbide metal oxide semiconductor field effect transistor (MOSFET) can be employed as a power semiconductor switching device. Normally-off operation can be obtained with SiC MOSFET technology. However, MOS-channel mobility of a silicon carbide MOSFET remains low after decades of technological advancements with respect to a MOSFET. Moreover, low MOS-channel mobility of a silicon carbide MOSFET can lead to undesired channel resistance. A junction gate field-effect transistor (JFET) can also be employed as a power semiconductor switching device. However, normally-off operation is difficult to achieve for a JFET. Furthermore, gate-to-drain capacitance of a JFET is generally large compared to other semiconductor devices, adversely impacting switching speed. SiC MOSFET and JFET devices are also generally vertical devices, with current flowing from a top portion of a semiconductor wafer to a backside portion of the semiconductor wafer where a drain electrode is generally formed. Vertical power devices are generally associated with increased vertical thickness rather than an increase in a lateral size (e.g., a device area) of the vertical power devices.
Additionally, a gallium nitride (GaN) based high electron mobility transistor (HEMT) can be employed as a power semiconductor switching device. A GaN HEMT is generally a lateral device with a high-mobility channel. However, in high-voltage power switching operation, high E-field can induce numerous reliability issues and/or stability issues such as current collapse (or dynamic on-resistance degradation) induced by surface and bulk traps, gate leakage, gate dielectric reliability degradation, etc. Scaling up the breakdown voltage in lateral devices can be achieved by increasing distance between a gate electrode and a drain terminal, which are generally both located on top of a semiconductor wafer. As a result, a larger device area is generally required for lateral devices.
The above-described background relating to conventional semiconductor devices is merely intended to provide a contextual overview of some current issues, and is not intended to be exhaustive. Other contextual information may become further apparent upon review of the following detailed description.